On Thu, 21 Sep 2000, Monte Goulding wrote:

> I've been reading the list heaps and finding out almost all that I need to 
> know at this stage but I have one big problem.
> I am developing a stack that needs to redraw an ellipse and a circular arc 
> that intersects with the ellipse at two points. I thought that the oval 
> graphic was the best tool for the job but how do I find the intersection 
> points. The rect of the arc is set and the user sets the rect of the 
> ellipse. I really only need to know the x coordinates so I can calculate the 
> arcAngle and the startAngle of the arc.
> My understanding is that an oval has no real mathematical definition so is 
> the oval tool actually an ellipse?

Yes: Blame the HyperCard developers for this abuse of mathematical
terminology, which we just followed.

> If so can I obtain the submajor and 
> subminor axes of that ellipse?

Given the imprecision associated with drawing ellipses and the
differences in how they're drawn on the different platforms (and
believe me, we've tried long and hard to eliminate or at least
minimize these) IMHO you're probably not going to be able to do what
you want using this style of graphic.  Instead, I recommend using a
polygon object and generating the points of the arcs and ellipses (and
whatever other shapes you need) with scripts.  This way you can be
exactly sure where the points are, and that you have enough of them
to make a smooth shape at any size.  It does require a little math
(high-school geometry), but doing it this way will save you a lot of
time and headache in the long run.

> My other big question was why when we build a standalone there is no 
> facility to set icons for that standalone other than 0(standalone builder 
> custom prop mcappicon). I am planning to modify the standalone builder so 
> that i can set an icon for a custom file type as icon 1(standalone builder 
> custom prop mcdocicon). Is this modification a breach of license or 
> anything? It would be really good If in future versions of MetaCard the 
> engine had a couple more dummy icons in icon 2 & 3 so we could play with 
> these too.

There are two icons in the Win32 engine, one for the app and one for a
document icon.  You can change the first using the standalone builder,
but you'd have to change the second with an icon editor (like
AX-Icons) that can edit icons in place.  I'll submit a feature-request
for a way to change the second one in the standalone builder too.

> Regards
> Monte Goulding

Scott Raney  [EMAIL PROTECTED]  http://www.metacard.com
MetaCard: You know, there's an easier way to do that...

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